On certain scripts I get a internal server error when phpsuexec is installed (they all work fine without it). When I check the error log for these scripts all I see is "Premature end of script headers". I have checked suexec_log as well and there is nothing unusual. The one script (Filebrowsers thumbnailer) only causes an internal server error when thumbnailing large images (over 2 MB) and with the other script (Drupals module page under administer) I only get this error when I upload more than 1 extra module. These are the only scripts I have found any problems with so far. I have tried replacing/reinstalling them several times and they all have the correct permissions. What else should I check and how do I fix this? I am completely baffled.